The invention relates to an internal combustion engine which may be internally or externally ignited and may be supplied with a combustible fuel-air mixture in any known and suitable manner, for example by carburetion or by fuel injection. The engine may be of the 4-cycle type, performing successive intake, compression, power and exhaust strokes.
In known 4-cycle engines of this type, a sliding or rotating and sliding piston compresses a fuel-air mixture in a combustion chamber. The sliding friction between the piston or piston seals and the cylinder wall is reduced by continuous lubrication requiring extensive auxiliary equipment e.g. an oil sump, an oil pump, multiple conduits, etc. In addition, the compression seal of such an engine is always imperfect, even when all parts are new, and gradually deteriorates even further due to wear. Furthermore, oil leaking into the combustion chamber produces smoke and other harmful substances which are vented to the atmosphere.